Propeller



June 16, 1936. A. A. HANDL;R 2,044,295

PROPELLER Filed Aug. 28, 1929 Patented June 16, 1936 UNITED STATES PATENT QFFEGE PROPELLER of Pennsylvania Application August 28, 1929, Serial No. 388,869

28 Claims.

This invention has to do with the art of propellers and is particularly concerned with the provision of metallic propellers of novel construction and grain structure.

Products made by propeller manufacturing methods prior to the present invention have hub portions of metal that are not worked to the same extent as is the metal of the blade portion. This is because the methods are lacking in any processes for individually working the metal of the hub portion. When the hub portions are of a construction other than cylindrical, that is with any structure such as outstanding flanges or the like thereon, the flow lines of the metal do not conform to the contour of the hub.

A flow line in a wrought metal bears a certain relation to fiber in wood and the term fiber" has come into quite common usage in the wrought metal field. It has been defined as a condition of parallelism of lines or structural details and may frequently be found in any wrought metal. On visual examination it may show itself through undissolved constituents, segregations, or nonmetallic inclusions. Grains may quite often be found to be elongated in the direction of the fiber and the fiber will parallel the direction of the previous working.

Fiber, or flow lines as I term them, may sometimes be visible to the unaided eye when a specimen of wrought metal is deeply etched, or may be apparent only on microscopic examination. Going even further, certain types ofv flow lines caused by preferred orientations of crystal axes are only distinguishable by X-ray analyses.

Since as stated above the flow lines do not conform to the contour of the hub, the latter is thereby rendered less resistant to the stresses encountered in service than would be the case if the flow lines did conform to the contour. The prior art constructions are lacking in metallic propellers of this type having axially recessed hub portions which are of importance in the field of aeronautics.

With the foregoing in mind, this invention provides a metallic propeller having a hub portion in which the fiow lines of the metal conform in direction to the contour of the hub. The invention also has as an object a metallic propeller which has a recessed hub portion, and which recess preferably extends axially thereof into the blade portion of the propeller.

I propose to pierce the hub portion of a propeller, extruding or upsetting the metal thereof in order to provide a product in accordance with the above noted throughts. More specifically it is my idea to upset or extrude the metal of the hub and blade adjacent thereto by a series of piercing operations which gradually bring the hub into its ultimate shape.

With these and other more detailed objects and advantages in view, as will in part become apparent, and in part be hereinafter stated, the invention comprises certain novel constructions, combinations, and arrangement of parts as will be subsequently specified and claimed.

For a full and more complete understanding of the invention, reference may be had to the following description and accompanying drawing,

wherein,

Figure 1 is aplan view of a propellermade in accordance with this invention.

Figure 2 is a section taken about on the line 2-2 of Figure 1, and,

Figure 3 is a section taken approximately on the line 3-3 of Figure 1, and,

For illustrative purposes the instant description is directed'to an aeronautical propeller. It is to be understood, however, that propellers of any type designed for operation in fluids that fall within the language of the claims appended hereto are intended to be within the purview of the invention.

In a preferred form the propeller is made from an aluminum base alloy. Such an alloy has an aluminum content of about ninety-four percent and contains approximately 4.5 percentcopper and .75 percent manganese, and .75 percent silicon. However, any suitable metal could well be employed in lieu of the material noted; iron and steel, magnesium and its base alloys, copper combinations, such as brass and bronze, and nickel in combined form, such as monel metal, have been found to be suitable as material from which propellers may be made and I comprehend the use of any of these substances in accordance with the teachings of this invention and in lieu of aluminum place particular emphasis on the magnesium base alloys as the latter exhibit nearly all the desirable qualities when employed for propeller purposes.

A propeller, such as I propose to provide, is shown in Figure 1 and designated generally A. For the purpose of this description the propeller A is described as comprising a hub portion i and a blade portion 2, which are integral. These portions are formed from an ingot or billet of the aluminum base alloy above noted by a method to be hereinafter more fully set out.

The recess or hollow 3 is of an irregular shape. Near the flanged end and co-extensive with the hub of the propeller, the recess is circular as shown in Figure 3, but as the opening 3 recedes into the blade portion it gradually flattens out to conform to the shape of the propeller. This is developed in Figure 2.

The hub portion 2 is substantially cylindrical in shape and at its free end is formed with outstanding flanges 4 which constitute a hub mounting. A slight taper indicated at 5 connects the flanged portion with the cylindrical portion of the hub.

The metal of the propeller in the hub and blade portions is typical of hot wrought metal throughout, the crystals of which have been thoroughly worked. The metal is characterized by flow lines which conform in direction with the contour of the propeller in both the blade and hub portions and by grains which vary in size in a uniformly progressive manner throughout the article in accordance with the thickness of the metal therein. Any laminations which may appear as a part of the flow line arrangement take the order of the latter and any harmful effects thereof which ordinarily would exist are substantially obviated as far as propeller use is concerned. The grain structure is also practically free from coarse grains and transversely localized voids.

The properties of the metal set out in the preceding paragraph may be the result of the method of producing the propellers. Such a method in a preferred form embodies the process of rolling out an ingot or billet of the aluminum base alloy, while in a workable condition due to heating, into the general shape of a propeller. operations comprise a series of rolling steps which work the metal into the rough blade shape. The rolling is efiected by the operation of forging rolls and this step has the peculiar efl'ect of imparting to the propellers particularly in the blade portion thereof the qualities and characteristics above noted.

After being rolled out the roughly fashioned blade is subjected to the action of forging dies which serve to bring the blade portion more nearly into its final shape but leaves the hub of the propeller in the form of a short cylindrical portion integral with the blade portion.

Pressing operations may supplement, or be substituted for the forging by the use of dies, but in either case the result of the step is to leave the blade portion 2 practically finished while the hub portion remains unfinished in a solid condition.

The shaping of the blade portion is preferably carried out in this way and as claimed in my co-pending application Serial No. 383,017, filed August 19, 1929, to incorporate into the blade structure the novel metallic structure claimed in my co-pending application Serial No. 388,868, filed August 28, 1929.

At this point the handle portion or tong hold which has been provided for manipulating purposes is removed in any suitable manner as by cutting and the hub portion is fashioned into its final shape.

In carrying out the step last noted the hub portion is placed in a confining die and is pierced by a properly shaped tool to extrude and upset the metal into the die and thereby shape the propeller. The die is formed with grooves which define the flanges 4 while the piercing tool forms the hollow or recess 3. The hub portion is not formed into its final shape by one piercing operation, but is gradually Worked into this form by a series of piercing operations. The first of these The rolling out piercing steps merely forms outstanding flanges on the hub and an opening therein which is worked into the long gradually flattening recess by the subsequent operations. The formation of the desired metallic structure in the hub and root portion is preferably carried out in this way and as claimed in my Patent No. 1,927,499, issued May 8, 1934 on my co-pending application Serial No. 387,016.

In working the metal of the hub portion in this manner in some instances it is desired simply to upset and radially spread the metal during the piercing operation. This is accomplished by proper correlation of the size and of the die cavity and the piercing tools so that the cross sectional area of the metal in the hub and root portion is not changed, but the metal is simply displaced radially. In other instances and with certain metals it is desired to further work the material by extrusion. This is accomplished by using a larger piercer or smaller die cavity so that the metal in addition to being displaced outwardly is caused to extrude longitudinally. The metal is thus worked both by the upsetting and extrusion and has the characteristics of upset and extruded metal. I

A particular advantage of this construction is that in addition to working the metal at the hub and root portion of the blade so as to develop its maximum strength and fatigue resistance to correspond with the development of the strength of the metal which has been forged into the blade proper, the resistance of the hub to bending stresses is increased for a given cross sectional area. It is desirable to form the complete blade from a substantially cylindrical billet. The dir dc ameter of the billet is determined by the desired width and shape of the blade. With the present construction a billet can be used which has suificient metal in cross section to carry the longitudinal stresses imposed on the blade by centrifugal force and the like, but insufiicient resistance to bending stresses. The resistance of the hub portion to bending stresses can then be brought up to-the desired point by the radial displacement and enlargement of the hub portion.

After the hub has been formed the propeller is finished by the usual operations including cleaning, sizing, trimming, and heat treating.

What I claim is 1. In propellers, integral hub and blade portions of metal, the metal of the hub having a grain structure that is characteristic of the metal when upset.

2. A metal propeller of the class described com- 0 prising an integral metallic construction which has the characteristics of hot-wrought metal, part of said construction being formed with a recess.

3. A metallic propeller having a hollow hub and the grain structure of which is composed of grains which vary in size in a uniformly progressive manner and which is characterized by flow lines that conform in direction with the contour of the blade and hub portions of the propeller.

4. A metallic propeller having a recessed hub portion and of a grain structure comprising fine grains that vary in size in a uniformly progressive manner lengthwise of the propeller and in accordance with the thickness of the metal thereof.

5. A propeller consisting of apiece of light metal base alloy fashioned into a propeller shape having hub and blade portions, the blade portion having a solid tip, said propeller being formed with a recess extending through the hub 75 portion into the blade portion and which recess gradually flattens out to conform with the shape of the hub and blade portions respectively.

6. In propellers, a hub construction having a grain structure that is characteristic of the metal when upset.

7. In propellers, a hub construction comprising a piece of aluminum base alloy which has a grain structure that is characteristic of the alloy when extruded and upset.

8. A propeller consisting of blade and hub portions of an aluminum base alloy, the metal 01' the hub portion being pierced to provide a recess therein.

9. A propeller consisting of a. piece of an aluminum base alloy which has been worked into the propeller shape by operations extruding and upsetting the alloy, the alloy having flow lines conforming in direction to the contour of the propeller.

10. In propellers, a blade having a hollow hub portion and a solid blade portion, and composed of an aluminum base alloy having a fine grain structure throughout the hub and blade portions and which is characteristic of the alloy when hot-worked.

11. A propeller of the class described consisting of a single piece of an aluminum base alloy having a grain structure characteristic of the alloy when wrought and comprising a flattened solid blade portion and a rounded recessed hub portion, and an outwardly extending flange on the hub portion.

12. A propeller blade of the class described consisting of a piece of an aluminum base alloy having a grain structure characteristic of the alloy when wrought and comprising a substantially cylindrical hub portion, and a flattened blade portion, having a recess extending thereinto, the recess being substantially circular at one end of the hub portion and varying in cross-sectional shape to a narrow flattened shape at its closed end in the blade portion.

13. In propellers, a hub construction consisting of a single piece of an aluminum base alloy which has been pierced to provide a recess extending lengthwise of the hub.

14. In a propeller, a hub portion consisting of a single piece of metal worked into a hub shape having a recess therein and which metal has a structure that is characteristic of the metal when extruded and upset.

15. In a propeller, a hub portion having an opening therein, said hub portion being of extruded metal having a refined grain structure characterized by flow lines that conformin direction with the contour of the hub.

16. In a metallic propeller of the class described, the combination, with a substantially solid blade portion of thin cross-section, of a substantially cylindrical hub portion integrally connected to the blade portion by a portion that gradually merges into the shape of the blade, the propeller being formed with a recess extending from the hub into the blade and which recess conforms generally to the outside shape of the propeller.

1'7. In a metallic propeller of the class described, the combination, with a substantially solid blade portion of thin cross-section, of a substantially cylindrical hub portion integrally connected to the blade portion by a portion that gradually merges into the shape of the blade, the propeller being formed with a recess extending from the hub into the blade and which conforms generally to the outside shapeor the, propeller, said hub portion being formedwith outwardly extending flanges adjacent to the endthereoi.

18. A light metal propeller comprising integral blade and hub portions formed from a billet of 5 light metal alloy by the application of a deforming force, the hub portion being axiallypierced to provide a recess extending into the same and to further work the metal of the hub portion.

19. A light metal propeller fashioned from a In billet of light metal alloy and having a worked metallic structure, said propeller including a hub portion having an axial recess extending into the same, the metal of the hub portion being additionally worked by the formation of the recess.

20. A propeller blade consisting ofan integral piece of light metal alloy worked into the shape of a blade merging into and terminating in a substantially cylindrical hub portion, the blade having a metallic structure characterized by flow lines substantially conforming to the contour, and the end of the hub portion being radially enlarged and having a metallic structure including flow lines in continuation of the flow lines of the blade and conforming to the contour of the hub portion.

21. A propeller blade consisting oi an integral piece of light metal such as aluminum or aluminum alloy having aflattened blade portion merging into and terminating in a substantially cylindrical hub portion, the blade portion having a wroughtmetallic structure characterized by substantially uniformly refined grains, and the hub portion being radially enlarged at its end and having a wrought fine grained metallic structure with grains of substantially the same size as those in the blade portion merging into the structure of the blade portion without excessive grain size contrast.

22. A propeller blade consisting of anintegral piece of light metal such as aluminum or aluminum alloy having a flattened blade portion merging into and terminating in a substantially cylindrical hub portion, the blade portion having as a wrought metallic structure characterized by substantially uniformly refined grains and the hub portion having a wrought fine ed metallic structure with grains of substantially the same size as those in the blade portion mergso ing into the structure of the blade portion-without excessive grain size contrast.

23. A propeller blade consisting of an int piece of light metal such as aluminum or aluminum alloy having a flattened blade portion merging into and terminating in a =v-tially cylindrical hub portion, the hub portion being radially enlarged at its end and having a wrought fine grained metallic structure with flow lines conforming to the contour of the en- Larged end and extending generally axially oi the lade.

24. A propeller blade consisting of an inte piece of light metal such as aluminum or aluminum alloy having a flattened bladeportion merging into and terminating in a substantially cylindrical hub portion, the hub portion being radially enlarged at its end and having a wrought. fine grained metallic structure with flow lines conforming to the contour of the enlarged end and extending generally axially of the blade, the gi-Eins of the hub portion being substantially muformly refined and merging with the blade portion without excessive grain size contrast.

25. A propeller blade consisting of an integral piece of light metal such as aluminum or anuminum alloy having a flattened wrought blade portion merging into and terminating in a substantially cylindrical hub portion, the hub portion being axially pierced and upset and having a wrought fine grained metallic structure with flow lines conforming to the contour thereof.

26. A propeller blade consisting of an integral piece of light metal such as aluminum or aluminum alloy wrought throughout having a flattened wrought blade portion merging into and terminating in a substantially cylindrical hub portion, the hub portion axially pierced and provided with an upset flange.

27. A propeller blade consisting of an integral piece of light metal such as aluminum or aluminum alloy wrought throughout, the hub and root portion of the flattened blade part of said propeller proportioned to have substantially the same metallic cross sectional area, the metal of the end 01 the hub portion being displaced raleaving an axial opening in the hub end of the propeller and thereby increasing the effective bending strength of the propeller at the hub.

28. A propeller blade consisting of an integral piece 01' light metal such as aluminum or aluminum alloy wrought throughout, the hub and the root portion of the flattened blade part of said propeller proportioned to have substantially the same metallic cross sectional area, the metal of the end of the hub portion being displaced radially from the longitudinal axis of the propeller, leaving an axial opening in the hub end of the propeller and thereby increasing the efiective bending strength of the propeller at this point, and an upset flange formed on said recessed hub portion to facilitate the mounting of said propeller blade.

ALFRED A. HANDLER. 

